The semiconductor industry has experienced rapid growth in recent years. Technological advances in semiconductor materials and design have produced various types of devices that serve different purposes. The fabrication of some types of these devices may require forming one or more III-V group compound layer on a substrate, for example forming a gallium nitride layer on a substrate. Devices using III-V group compounds may include light-emitting diode (LED) devices, laser diode (LD) devices, radio frequency (RF) devices, high electron mobility transistor (HEMT) devices, and/or high power semiconductor devices.
Traditionally, manufacturers have formed the III-V group compound layer on a sapphire substrate. However, sapphire substrates are expensive. Thus, some manufacturers have been attempting to form III-V group compound layers on a silicon substrate, which is cheaper. However, due to lattice constant mismatches and the different thermal expansion coefficients between the III-V group compound layer and the silicon substrate, existing methods of forming a III-V group compound layer on a silicon substrate may result in wafer defects (e.g., cracking defects) or yield low quality III-V group compound layers.
Therefore, while existing methods of forming III-V group compound layers on silicon substrates have been generally adequate for their intended purposes, they have not been entirely satisfactory in every aspect. A method of growing high quality III-V group compound layers on a silicon layer without defects such as cracking continues to be sought.